All money from the auction goes to a charity. In this case, it's to The Writer's Guild Foundation Industry Support Fund, which is basically a charity for people affected by the Writer's Strike who can't pay for their lives any other way.
I'm signed up for ficwriting, and I'd encourage anyone out there capable of doing the whole fanworks thing to sign up as well. Registration for the auction ends tomorrow, at 11 PM GMT, so get in quickly if you're gonna!